Jig



May 7, 1929. H BIEDER 1,712,453

JIG

Filed Jan. 25, 1926 Eug; A A E lll fill

rented may 7,

'HERMAN BIEDER, OF CLEVELAND, OHIO.

JIG.

i Application filed. January 25, `1926. Serial No. 83,524.

llfly invention relates to jigs, and prinjiarily to lgs used for drilling holes in metal objects. '.llhe object of the invention is to provide a so constructed that a minimum wear on and hence longer life ofthe drill is produced,

`as a result of whichthe quality of the article drilled enhanced, in consequence of the elimination of the burr-s which are usually formed upon the drilled object.

The said invention involves primarily the introduction intermediately of the drill and the jig, of a metal softer than the drill and having` a guiding aperture coaxial with the guiding aperture of the main jig member.

lleretoforc it has been customary to maire jigs or the bushings in jigs of `this class of very hard steel, as such hardness is obviously necessary in order to secure accuracy in the drillingoperation. These apertures are' so necessarily very nearly the size of the 'ill and the latter therefore often, while be- 9, forced into alinement, comes in Contact with the hard upper edge of the guiding aperture or the interior guiding surfaces of these apertures and its cutting edges become dulled in consequence. This drilling detracts from the efficiency and life of the drill and produces burr-s at the fartherend of the holes of the drilled object, whose removal involves expense and, hence, loss. i i

rlhe said invention consists of means hereinafter fully described and particularly set forth in the claims.

al di The annexed drawing and. thefollowing' description set forth in detail certain means for carrying out my invention, the disclosed means, however, constituting;- but one of the various mechanical forms in which the principle of my invention maybe employed.

Tn said annexed drawing llin'ure l represents a cross-sectional view of a embodying my invention showinga piece of worlr in place, and a holder for secarino' the and piece of work while the latter is being drilled; i y

lling. 2 represents a plan of the jig shown in l*1 l. j

llifr. 3 represents view similar to that of lila. l showing a modified form.

lilies. fl. and represent cross-sectional views of still further modiiications of the lli 6 represents a fragmentary cross-section of a further modification.

ln the embodiment of my invention, illus-` struction is provided, having the clamping screw 2 and formed with the recess 8 adapted to receive the particular j ig employed, which later is clamped against the side walls of the holder by means of the said clamping screw 2.

The jig comprises two parts, a main or primary member 4 made of hard steel and formed with the bottom recess 5 for receiving and fitting Ltheparticular piece of work to be drilled, in this instance shown to be a rec tangular block 6 provided with two bosses (3Q-G', through which it isrequired to drill parallel' holes.

This main or primary member is provided with two guiding apertures 7 7, whose axes are parallel and perpendicular to the face of the jig, the upper ends of these apertures being preferably flared as at 8. This primary member is made of hard steel so that the interior of the guiding apertures 77 present hard steel surfaces. Secured to the upper face of the primary member 4 of the jig'is a plate 9.1 nade of metal softer than that usual ly employed for a drill, such as, for instance, brass. This plate or secondary jig member is ixedly secured to the primary member by means of suitable screws 10--10. This secondary member is furthermoreprovided with two guiding; apertures 11-11 preferably flared at their outer ends as at 12,'these apertures being coaxial with and of the same diameter as the guiding apertures 7-7.

When the above-described device is utilized, thc `holder with the described parts attached thereto is placed in suitable positionbeneath the drill 13 by hand and as nearly as possible in alinement with the aperture over the place to be drilled as is the usual custom. The drill is then rotated by suitable means (not shown) and then lowered to engage the guiding aperture l1 which is `immediately beneath it. The end of the drill, therefore, if out of exa ct alinement first comes in contact with the soft guiding; surface of thesecondarymem `her andfbv itscontact therewith accurately alines the beneath such drill. By the time, therefore, "that the latter reaches the hard guiding surface of the aperture 7 it will be in perfect alinement and hence not come in Contact with the upper edge of such h ard surface. `By further depressing the drill, the required hole is made in the work 6 and the labove operation is repeated in drilling the other holes, as will. be readily understood.

Cil

In Fig. 3, I have shown the main or primary member 4 which may be of ordinary steel provided with the bushings 14 which are made of steel of the required hardness and whose apertures 7 form the hard guiding surfaces. Instead of placing the secondary kforming a space 16 readily -removed laterally during the drilling In' Fig. 4 I have shown a jig construction similar to Vthat shown in Fig. 3, but instead t of-beingl held away from the upper surface securing the required general result, which `:of the primary member by separators, the secon'dary memberrests directly upon the upper ends of the bushings 14.

In Fig. 5 l have shown another way of consists in providing bushings-14, such as are shown inY Figs. Sand 4, the said bushings, however, being each provided with a Vflange 17 which receives the reduced end of a soft metal sleeve 18 having a bore 190i thesaine diameter as the inner bore of the bushings Vand flared at its upper end. In

`'this case'a multiplicity of secondary soft Ymetal guiding members is provided, instead of one,` as shown in Figs. 1 and 2, the prineiple involved, however, being the same.

f In Figure 6 I have shown a modification lof theconstructio'n shown in Fig.v 5 in which 'Iemploy 'a bushing similar to those shown in Figs. 3 and 4-1and separate secondary meinbers each of w ich is provided with a lower recess 2O` for receiving the upper or flange endlof the bushings. j These sleeves are made ofsoft'metal as in the case of the other and previously described secondary members and provided with flared apertures 21.V

As before stated, I have found that by the usefroff this intermediate soft metal member [which receives the lirst contact of the drill, the lattery is prevented from coming into contactwith the hard guiding surface of the jig, before the drill is alined accurately therewith'.v rIhis has resulted, in actual experience. of a greatlyincreased life of thed'rill without sharpening andfhas also resulted inthe substantialelimination of buirs at the lower oi' 'farther endof the holes drilled in the work. The term fprimary member7 as herein used isjto'jbe' interpreted as the main member of the jig and which is placed and is directly in contact with the article to be drilled.

ll'hat I claim is:

1. In a jig, the combination of a main meniber provided with a guiding aperture whose guiding surface is iliade of hard steel; of a secondary member iixedly mounted with respect to said main member and provided with a guiding aperture whose guiding surface is made of metal softer than that of an ordinary drill and which is coaxial with and substantially ofthe same diameter as said tirst-named aperture.

2. In a jig, the combination with a main member provided with a guiding aperture whose guidingl surface is made ot hard steel: ot' a secondary member disposed outside of; said main member, fixed to the latter, and having a guiding aperture whose guiding sur- 'tace is made of soft metal such as brass, said apertures being coaxial.

In a jig, the combination with a` inain member comprising a body portion having an aperture passing therethrough, and a stccl bushing in such a )crturc whose interior .forms a guiding sur act` for a drill; of a secondary member :associated with and ixed respectively to said bushing and having a guid` ing aperture of substantially the saine diameter and coaxial with thc aperture of said bushing; said secondary member being made of soft metal such as brass.

4. In a jig, the combination with a main member comprising a body portion having an aperture passing therethrough, and a steel bushing in such aperture whosii interior forms a guiding surface for a drill; of a secondary memberin the form of a bushing fixed exteriorly of said body portion to an end oit the first-named bushing and made of soft metal such as brass. Y

5. In a the combination with a main member provided with a cylindrical hole passing therethrough whose surface is formed of hard steel; of a secondary member tixedly mounted with respect to and abovel said main member and having a cylindrical hole therein coaxial with the hole of said main member Vand whoselower end portion has a .diameter equal to that ofthe hole in the main member; said secondary member bcin j made of metal materially softer than that o an ordinary drill.

Signed by me this 1G day of January, 1926.

H. BIEDER. 

